Both Cmd and Opt change songs :(

[soccersquirt82]

I would like only Cmd (arrow) to change songs, but Opt (arrow) changes the songs as well. How do I get rid of the Opt shortcut? The Cmd shortcut comes from Quicksilver. It works from every application. I don't know where the Opt shortcut came from and it only works from iTunes. I can't find that preference. I've looked in Keyboard shortcuts from System Preferences and in Preferences in iTunes. Help!